Twenty Years of Ecological Change in Arctic Muscidae (Diptera) at Zackenberg, Greenland
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Twenty years of ecological change in Arctic Muscidae (Diptera) at Zackenberg, Greenland By Sarah Loboda Department of Natural Resource Sciences McGill University, Montreal August 2020 A thesis submitted to McGill University in partial fulfillment of the requirements for the degree of Doctor of Philosophy © Sarah Loboda, 2020 1 ‘The truth is that we need invertebrates but they don’t need us. If human beings were to disappear tomorrow, the world would go on with little change. (…) But if invertebrates were to disappear, I doubt that the human species could last more than a few months.’ Wilson (1987) 2 Dedication This thesis is dedicated to Terry Wheeler, a passionate entomologist, outdoor enthusiast, talented speaker, and teacher. He was the person I enjoyed the most going to conferences with, chasing great talks. Without him, I would not have made the jump in the adventure of a Ph.D. 3 Table of Contents Dedication ..................................................................................................................................... 3 Table of Contents .......................................................................................................................... 4 Abstract ......................................................................................................................................... 7 Résumé ......................................................................................................................................... 9 Acknowledgments ...................................................................................................................... 11 List of Figures ............................................................................................................................. 13 List of Tables .............................................................................................................................. 16 Contribution of authors ............................................................................................................... 18 Contributions to original knowledge .......................................................................................... 19 Introduction and objectives ......................................................................................................... 22 Introduction ................................................................................................................................ 22 Research objectives and outline ................................................................................................. 23 Chapter 1 Literature review ........................................................................................................ 24 1.1 Insects and their recent decline ............................................................................................. 24 1.2 The Arctic region under climate change ............................................................................... 26 1.3 Impacts of climate change on global and Arctic biodiversity .............................................. 29 1.3.1 Diversity and composition ............................................................................................. 29 1.3.2 Phenology ...................................................................................................................... 30 1.3.3 Development and life cycle ........................................................................................... 34 1.3.4 Phenology and population dynamics ............................................................................. 35 1.4 Long term monitoring and the special case of Zackenberg .................................................. 36 1.5 Diptera and Muscidae ........................................................................................................... 37 Linking statement ......................................................................................................................... 40 Chapter 2 Declining diversity and abundance of High Arctic fly assemblages over two decades of rapid climate warming .............................................................................................. 41 2.1 Abstract ................................................................................................................................. 41 2.2 Introduction .......................................................................................................................... 42 2.3 Materials and methods .......................................................................................................... 45 2.3.1 Study area and data collection ....................................................................................... 45 2.3.2 Data analyses ................................................................................................................. 47 2.4 Results .................................................................................................................................. 51 2.4.1 Climate change at Zackenberg ....................................................................................... 51 4 2.4.2 General results on muscid assemblages ......................................................................... 52 2.4.3 Temporal patterns of muscid abundance ....................................................................... 55 2.4.4 Temporal patterns of muscid diversity........................................................................... 55 2.4.5 Temporal patterns of muscid assemblage composition ................................................. 57 2.4.6 Relationship between species responses and environmental changes ........................... 59 2.5 Discussion ............................................................................................................................. 62 2.6 Acknowledgements .............................................................................................................. 67 2.7 References ............................................................................................................................ 67 Linking statement ......................................................................................................................... 77 Chapter 3 Earlier and shorter flight periods of small-bodied Arctic fly species linked to declining abundances ................................................................................................................... 78 3.1 Abstract ................................................................................................................................. 78 3.2 Introduction .......................................................................................................................... 79 3.3 Materials and methods .......................................................................................................... 82 3.3.1 Study site and data collection......................................................................................... 82 3.3.2 Analyses ......................................................................................................................... 82 3.4 Results .................................................................................................................................. 87 3.4.1 Phenology of the flight season ....................................................................................... 87 3.4.2 Species’ traits and species phenology ............................................................................ 92 3.4.3 Species phenology and abundance ................................................................................. 93 3.5 Discussion ............................................................................................................................. 96 3.6 Acknowledgements ............................................................................................................ 100 3.7 References .......................................................................................................................... 101 Linking statement ....................................................................................................................... 111 Chapter 4 Declining abundance of High-Arctic muscid flies (Diptera: Muscidae) associated with a reduction of the reproductive period over two decades of rapid warming ............... 112 4.1 Abstract ............................................................................................................................... 112 4.2 Introduction ........................................................................................................................ 113 4.3 Material and methods ......................................................................................................... 116 4.3.1 Study site and data collection....................................................................................... 116 4.3.2 Statistical analyses ....................................................................................................... 117 4.4 Results ................................................................................................................................ 122 4.4.1 Temporal trend in sex-specific abundance and sex ratio ............................................. 122 5 4.4.2 Temporal trends in sex-specific phenology and the reproductive period .................... 124 4.4.3 Sex-specific